No one knows if there is presently life on Mars or
if there was life in the past there that has
become extinct.What we do know is that IF there is
life, it is microbial. That is there are no plants
or animals.Basically, we will not really know
until we go there or study it with very
sophisticated robots.

Answer 2:

Nobody knows. That's the reason why we're looking
for it. Of all of the places in the universe where
there might be life, apart from Earth of course,
Mars looks like the most likely possibility. And
the possibility is very real, but we've not found
it yet.

Answer 3:

There is no proof that life exists on Mars but
there is evidence that may suggest there is or was
life on Mars. A meteorite was found in Antarctica
that came from Mars and some of the chemicals and
fossilized patterns found on the meteorite could
possibly have originated from a living organism
that was similar to bacteria. However, there is
much controversy on whether or not the chemicals
and fossilized patterns actually originated from
Mars or are contaminants from the environment in
Antarctica. More recently scientists have
discovered that the gas methane exists in the Mars
atmosphere which suggests that either a volcano
had recently erupted causing the methane gas or a
life-form similar to some bacteria on Earth is
metabolizing carbon dioxide and hydrogen,
producing the methane gas. Other gases and
chemicals in the Mars atmosphere are metabolic
waste-products of certain life-forms on Earth,
suggesting that life may have caused these
chemicals to exist on Mars.I think there is a
pretty good chance of life having existed on Mars
and maybe still existing today. But I think that
any life forms on Mars will be very primitive,
similar to bacteria and microbial life on Earth.